| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
25 Apr 2006 06:08:27 PM |
| Object: |
twin paradox for simple minds. |
is this possible?
i checked out the for dummies version, and it still confuses me.
im doing a presentation for a 200 level astronomy class i'm in, and
this topic is baffling me.
HELP PLEASE!!!!
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| User: "Hexenmeister" |
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| Title: Re: twin paradox for simple minds. |
26 Apr 2006 12:41:05 PM |
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<trey1967a@yahoo.com> wrote in message
news:1146006507.645363.266600@i40g2000cwc.googlegroups.com...
| is this possible?
|
| i checked out the for dummies version, and it still confuses me.
|
| im doing a presentation for a 200 level astronomy class i'm in, and
| this topic is baffling me.
|
| HELP PLEASE!!!!
No, it is not possible.
Androcles.
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| User: "Sam Wormley" |
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| Title: Re: twin paradox for simple minds. |
25 Apr 2006 09:35:39 PM |
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wrote:
is this possible?
i checked out the for dummies version, and it still confuses me.
im doing a presentation for a 200 level astronomy class i'm in, and
this topic is baffling me.
HELP PLEASE!!!!
Try: http://en.wikipedia.org/wiki/Twins_paradox#Resolution_of_the_Paradox_in_Special_Relativity
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| User: "Boris Mohar" |
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| Title: Re: twin paradox for simple minds. |
25 Apr 2006 08:46:16 PM |
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On 25 Apr 2006 16:08:27 -0700, wrote:
is this possible?
i checked out the for dummies version, and it still confuses me.
im doing a presentation for a 200 level astronomy class i'm in, and
this topic is baffling me.
HELP PLEASE!!!!
Is what possible?
--
Boris Mohar
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
29 Apr 2006 11:00:12 PM |
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On Tue, 25 Apr 2006 16:08:27 -0700, trey1967a wrote:
is this possible?
i checked out the for dummies version, and it still confuses me.
im doing a presentation for a 200 level astronomy class i'm in, and
this topic is baffling me.
HELP PLEASE!!!!
The standard formulation is along the lines of the following:
A and B are twins. A boards a rocket, instantaneously accelerates to a
velocity v, goes to a distant star L length-units away, accelerates some
more to return, travels back to Earth, notices that B has aged
considerably. (The theoretical ratio turns out to be sqrt(1-v^2/c^2),
assuming outbound and return trips are at the same cruising speed v.)
Of course for any interesting velocity v A would be squished to a pancake.
If A can tolerate a maximum of 100 N/kg (10 'gees', approximately, in
fighter pilot parlance; 1 gee = 9.805 N/kg or 9.805 m/s/s), then it will
take him 3 * 10^6 seconds = 34 days, 17 hours, 20 minutes to get to
lightspeed, assuming Newtonian/Galilean math, which doesn't quite hold
true anyway. (It would be a brutal month, too.)
A simple calculation using the Rocket Equation can also be done, but this
post already goes overlong.
The simplest method for me to analyze the Twin Paradox would be to set up
two events. The first event is at the origin (Earth), and is of course
(x,t) = (0,0). The second event is some distance (L) away, at a time (t)
which is yet to be determined.
You are, I trust, familiar with the Lorentz transformation, which I'll
represent here as
g = 1/sqrt(1-v^2/c^2)
x_B = (x_A - v * t_A) * g
t_B = (t_A - v * x_A / c^2) * g
where (x_A,t_A) is A's coordinate system, and (x_B,t_B) is B's.
The transform is easily invertible, yielding the expected result:
x_A = (x_B + v * t_B) * g
t_A = (t_B + v * x_B / c^2) * g
which is also the result one would get if one switches A and B and changes
v's sign.
This is a coordinate transformation; one has to be careful in applying it.
An observer cannot observe something unless it hits his eyeballs (or his
instruments) at the point x = 0. (It took me awhile to figure this out.)
The launch is at (0,0) in both systems (the Lorentz requires that the
origins coincide in any case). Assuming we know L, how long does it take
B to reach the star?
That's easy enough. B reaches the star when x_A = L and x_B = 0; this
requires
0 = (L - v * t_A) * g
t_A = L/v
Fine, but what's t_B ? OK, that's computable as well:
t_B = (t_A - v * x_A / c^2) * g
t_B = (L/v - v * L/c^2) * g
t_B = (L/v) * (1 - v^2/c^2) * g = (L/v) / g
since 1/g^2 = 1-v^2/c^2.
For the return trip one can either run the movie backwards or recalculate
t_B given x_A = -L and x_B = 0. Total time: 2L/v for A, 2L/(vg) for B.
A is therefore older.
There are some interesting issues if one gives cameras to A and B which
transmit information at lightspeed. For starters, if A is at the point
(0,L/(vg))_A, B sees that point as (L,L/v)_B, though not instantaneously;
the light (radio signals count as light here) must travel back to B at
speed c which means B sees A turn around at time L/v+L/c. This means that
A's clock, as observed by B, runs at the rate
L/(vg) / (L/v+L/c) = sqrt(1-v^2/c^2) / (1 + v/c)
= sqrt(1-v/c)/sqrt(1+v/c).
During the trip back, one gets
L/(vg) / (L/c-L/v) = sqrt(1-v^2/c^2) / (1 - v/c)
= sqrt(1+v/c)/sqrt(1-v/c) -- the reciprocal.
I personally find this result aesthetically pleasing. :-) Not that the
Universe cares much for my artistic values. Note that for low v the
values
sqrt(1+v/c)/sqrt(1-v/c)
and
(1+v/c)
are almost equal -- the error, in fact, is sqrt(1-v^2/c^2) again.
One might also redo these computations using Galilean relativity; in
Galilean relativity the coordinate transform is
x_B = x_A - v * t_A
t_B = t_A
this is of course invertible to
x_A = x_B + v * t_B
t_A = t_B
and results in both sides observing time 2L/v for the trip, though A will
observe a peculiar anomaly as he will see B accelerating away from the
star at time L/v + L/(c+v) which is *before* he sees B approaching the
star at time L/v + L/(c-v). (Remember that Galilean relativity does not
postulate constant lightspeed.)
This is of course mathematical pontification but a fair amount of
experimentation backs up special relativity, as it turns out, and its more
general cousin, general relativity. In particular, detecting muons at sea
level with an energy level of 2 GeV cannot be explained using Galilean
theory unless one assumes that the muons are created less than 1 km up.
Airborne experiments do not show muons being created so low. SR explains
this anomaly fairly nicely.
You might also research de Sitter; AIUI he did some observations on
orbiting stars. More modern neutron star pairs are also available, which
show several artifacts predicted by SR and GR, especially since neutron
stars make dandy rotating beacons and clocks.
--
#191,
It's still legal to go .sigless.
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| User: "Hexenmeister" |
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| Title: Re: twin paradox for simple minds. |
30 Apr 2006 08:08:21 AM |
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"The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
news:pan.2006.04.30.03.17.56.268285@earthlink.net...
[snip for bevity]
| You are, I trust, familiar with the Lorentz transformation
[rest snipped]
No. Derive it for me.
Androcles.
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
06 May 2006 10:00:13 PM |
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On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
"The Ghost In The Machine" < > wrote in message
news:pan.2006.04.30.03.17.56.268285@earthlink.net...
[snip for bevity]
| You are, I trust, familiar with the Lorentz transformation
[rest snipped]
No. Derive it for me.
Androcles.
OK, from what? Be specific.
(Apologies for the delay, BTW. I only get to this group on weekends.)
--
#191,
It's still legal to go .sigless.
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| User: "Hexenmeister" |
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| Title: Re: twin paradox for simple minds. |
07 May 2006 03:55:35 AM |
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"The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
news:pan.2006.05.07.02.13.35.7621@earthlink.net...
| On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
|
| >
| > "The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
| > news:pan.2006.04.30.03.17.56.268285@earthlink.net...
| >
| > [snip for bevity]
| >
| > | You are, I trust, familiar with the Lorentz transformation
| >
| > [rest snipped]
| >
| > No. Derive it for me.
| > Androcles.
|
| OK, from what? Be specific.
Derive it any way you can, I'll still rip it to shreds. Easy to do, the
cuckoo
transformations are nonsense.
| (Apologies for the delay, BTW. I only get to this group on weekends.)
.
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
07 May 2006 12:00:04 PM |
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On Sun, 07 May 2006 08:55:35 +0000, Hexenmeister wrote:
"The Ghost In The Machine" < > wrote in message
news:pan.2006.05.07.02.13.35.7621@earthlink.net...
| On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
|
|
| > "The Ghost In The Machine" <> wrote in message
| > news:pan.2006.04.30.03.17.56.268285@earthlink.net...
| >
| > [snip for bevity]
| >
| > | You are, I trust, familiar with the Lorentz transformation
| >
| > [rest snipped]
| >
| > No. Derive it for me.
| > Androcles.
|
| OK, from what? Be specific.
Derive it any way you can, I'll still rip it to shreds. Easy to do, the
cuckoo
transformations are nonsense.
I need assumptions in order to derive it. Einstein's assumption was that
a TWLS experiment always returned c for lightspeed. However, there are
some errors in that explanation (mostly a confusion by the translator
and/or the author on what the term "speed" and the term "velocity" are)
which appear to be blocking your particular understanding.
This is not your assumption, obviously. I'd like to know what your
assumptions regarding lightspeed, light propagation, etc. are.
For reference, here's some that I happen to know a bit about.
[1] Absolute luminiferous aether theory. This theory assumes constant
lightspeed relative to a fixed, rigid aether. Time and space are absolute
regardless of motion.
[2] Newtonian relativity. This theory assumes constant lightspeed
relative to the source (in other words, all light pulses when immediately
measured at the source or by a destination motionless relative to the
source will have speed c). Time and space are also absolute.
[3] Einsteinian relativity. This theory assumes constant lightspeed for
all observers, moving or not. The "cuckoo transforms" are a mathematical
oddity derived therefrom, and time and space are not absolute but twist in
mind-bending fashion. These are "obviously wrong" since they are never
observed by the casual walker watching, say, cars or airplanes.
[4] H-Aether. This theory assumes, apparently, Newtonian relativity, with
an attenuator from a gaseous aether of maddeningly variable properties.
In short, this aether can cause light to speed up or slow down in
accordance with the author's whims.
[5] Kenseto. I have no idea precisely how to characterize his assumptions
except that they appear to be similar to Louis Savain's in general
principle, assuming an S-matrix lattice that is apparently fixed in space.
[6] Louis Savain (Probabilistic Particle Jump Theory). Photons describe a
cubical lattice and particles can interchange at lightspeed using this
lattice. Time and space are apparently absolute.
| (Apologies for the delay, BTW. I only get to this group on weekends.)
--
#191,
It's still legal to go .sigless.
.
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| User: "Eric Gisse" |
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| Title: Re: twin paradox for simple minds. |
06 May 2006 10:19:23 PM |
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The Ghost In The Machine wrote:
On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
"The Ghost In The Machine" < > wrote in message
news:pan.2006.04.30.03.17.56.268285@earthlink.net...
[snip for bevity]
| You are, I trust, familiar with the Lorentz transformation
[rest snipped]
No. Derive it for me.
Androcles.
OK, from what? Be specific.
(Apologies for the delay, BTW. I only get to this group on weekends.)
Do not let him take advantage of your neverending generosity. He has no
intention of understanding it when you derive it for him, as it has
been done at least a dozen times before over the years.
Androcles has no desire to learn special relativity.
--
#191,
It's still legal to go .sigless.
.
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
07 May 2006 01:00:06 PM |
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On Sat, 06 May 2006 20:19:23 -0700, Eric Gisse wrote:
The Ghost In The Machine wrote:
On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
"The Ghost In The Machine" < > wrote in message
news:pan.2006.04.30.03.17.56.268285@earthlink.net...
[snip for bevity]
| You are, I trust, familiar with the Lorentz transformation
[rest snipped]
No. Derive it for me.
Androcles.
OK, from what? Be specific.
(Apologies for the delay, BTW. I only get to this group on weekends.)
Do not let him take advantage of your neverending generosity. He has no
intention of understanding it when you derive it for him, as it has been
done at least a dozen times before over the years.
Androcles has no desire to learn special relativity.
No, but he does seem to love to flaunt his ignorance. Me, I might wave my
ignorance around a bit -- mostly because I don't know all that much about
particle physics. You might recall, for instance, a post about my
Ultimate Engine, a theoretical device that presupposes four protons
meeting and generating energy to propel a spacecraft. It certainly would
require a lot of work to develop and probably will never work as I
originally specified. (Uncle Al, shooting my dreams down like that.
:-) ) Most current fusion projects for some reason use deuterium and
tritium,and might suffer from the problem that tritium is radioactive;
from my impulse calculations the tritium is going to be a problem
traveling to, say, Sirius about 8 lightyears away with a transit speed of
about 80 years [*] or so, and that's assuming no heat loss. Frankly, I
don't know where they're going to get the tritium here on Earth, though
there's an occasional device powered thereby, mostly along the realm of
"glow-lights" or some such; I'd have to look.
(There was a piece about the poisonous nature of tritium escaping into the
environment, once it combines with carbon, oxygen, nitrogen, etc.; it is,
after all, hydrogen, chemically -- until the nucleus loses an electron.
Even deuterium is slightly problematic.)
Newtonian mechanics isn't too hard, compared to that, and in any event the
Ultimate Engine is merely an upper limit anyway; we can do no better
without a ready supply of antimatter, or some odd discovery of a Universal
quirk that allows for free energy -- the only thing that comes to mind in
that area is a little Asimovian piece about the discovery of zero gravity
by using electromagnetic fields, and the consequent generation of a harsh
ultraviolet field (from the air particles accelerated to lightspeed) and a
billiard ball. (I would forget the precise title but it had something to
do with billiards. It was included in Asimov's Mysteries. To give you an
idea of the fancifulness of his work, another piece had to do with the
O18->Fe57->Au79 (I think; I'd have to reread the piece) energy transition
in a fat goose's liver; this is of course extremely unlikely, but I happen
to like him. :-) )
[.sigsnip]
[*] this is well beyond contemporary engines, BTW.
--
#191,
It's still legal to go .sigless.
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| User: "Hexenmeister" |
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| Title: Re: twin paradox for simple minds. |
07 May 2006 03:38:23 PM |
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"The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
news:pan.2006.05.07.17.04.20.563633@earthlink.net...
| On Sat, 06 May 2006 20:19:23 -0700, Eric Gisse wrote:
|
| >
| > The Ghost In The Machine wrote:
| >> On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
| >>
| >>
| >> > "The Ghost In The Machine" <ewill3@earthlink.net> wrote in message
| >> > news:pan.2006.04.30.03.17.56.268285@earthlink.net...
| >> >
| >> > [snip for bevity]
| >> >
| >> > | You are, I trust, familiar with the Lorentz transformation
| >> >
| >> > [rest snipped]
| >> >
| >> > No. Derive it for me.
| >> > Androcles.
| >>
| >> OK, from what? Be specific.
| >>
| >> (Apologies for the delay, BTW. I only get to this group on weekends.)
| >
| > Do not let him take advantage of your neverending generosity. He has no
| > intention of understanding it when you derive it for him, as it has been
| > done at least a dozen times before over the years.
| >
| > Androcles has no desire to learn special relativity.
|
| No, but he does seem to love to flaunt his ignorance.
Hey *****! I know SR inside out and it's a hoax.
http://www.androcles01.pwp.blueyonder.co.uk/Smart/Smart.htm
{Drool snipped.}
Androcles
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
07 May 2006 06:00:04 PM |
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On Sun, 07 May 2006 20:38:23 +0000, Hexenmeister wrote:
"The Ghost In The Machine" < > wrote in message
news:pan.2006.05.07.17.04.20.563633@earthlink.net...
| On Sat, 06 May 2006 20:19:23 -0700, Eric Gisse wrote:
|
|
| > The Ghost In The Machine wrote:
| >> On Sun, 30 Apr 2006 13:08:21 +0000, Hexenmeister wrote:
| >>
| >>
| >> > "The Ghost In The Machine" <> wrote in message
| >> > news:pan.2006.04.30.03.17.56.268285@earthlink.net...
| >> >
| >> > [snip for bevity]
| >> >
| >> > | You are, I trust, familiar with the Lorentz transformation
| >> >
| >> > [rest snipped]
| >> >
| >> > No. Derive it for me.
| >> > Androcles.
| >>
| >> OK, from what? Be specific.
| >>
| >> (Apologies for the delay, BTW. I only get to this group on
| >> weekends.)
| >
| > Do not let him take advantage of your neverending generosity. He has
| > no intention of understanding it when you derive it for him, as it has
| > been done at least a dozen times before over the years.
| >
| > Androcles has no desire to learn special relativity.
|
| No, but he does seem to love to flaunt his ignorance.
Hey *****! I know SR inside out and it's a hoax.
http://www.androcles01.pwp.blueyonder.co.uk/Smart/Smart.htm
{Drool snipped.}
Androcles
Of course it is! That's why the Universe seems to agree with it more than
anything. Seems that Einstein flummoxed the entire Universe as well as
the whole of humanity (or at least the scientifically-literate subset
thereof), causing God to ensure that every measurement that we've been
able to make is consistent with SR and GTR's explanations thereof, from
the precession of Mercury to the so-called "superluminal muon" problem
(which is easily explained by SR, BTW) to the MMX experiment, which
started the entire fraudulent enterprise of Einstein's Tricks, Inc.
(currently about $300B or so in market capitalization). :-P
God is of course hopping sore that he bought into this Enterprise but
it's a bit late now. Allah of course is laughing loudly. The Great
Buddha is smirking, and Knowledgius Objectivus is quietly smiling as He
reads the newspaper of humanity's foibles. All four of them were of
course suckered.
But never mind; you seem to be of the opinion that the light curve of
Aql1493 and a trademark of Disney (complete with pointy hat) seem to prove
something. There are other light curves that may be more interesting to
study, such as PSR J0737-3039. (FSVO "light"; IIRC the radiation measured
here is more in the form of UV or soft X-rays.)
And you are, of course, free to postulate an alternative hypothesis such
as Henri Wilson's H-Aether, if said hypothesis can explain all of the
phenomena that is currently explained by SR and GTR.
--
#191,
It's still legal to go .sigless.
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| User: "Eric Gisse" |
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| Title: Re: twin paradox for simple minds. |
08 May 2006 01:56:55 AM |
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The Ghost In The Machine wrote:
[snip]
And you are, of course, free to postulate an alternative hypothesis such
as Henri Wilson's H-Aether, if said hypothesis can explain all of the
phenomena that is currently explained by SR and GTR.
Henri can fiddle with his computer program and get something that looks
reasonably similar to a star's brightness curve, but he is unable to
work with anything simpler. Such as planetary orbits, for example. He
throws up a smokescreen of excuses for why Newton gets it wrong and GR
gets it right, and then moves on to a different subject that he can
drag you down into with his stupidity.
--
#191,
It's still legal to go .sigless.
.
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| User: "The Ghost In The Machine" |
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| Title: Re: twin paradox for simple minds. |
08 May 2006 10:00:03 AM |
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On Sun, 07 May 2006 23:56:55 -0700, Eric Gisse wrote:
The Ghost In The Machine wrote:
[snip]
And you are, of course, free to postulate an alternative hypothesis such
as Henri Wilson's H-Aether, if said hypothesis can explain all of the
phenomena that is currently explained by SR and GTR.
Henri can fiddle with his computer program and get something that looks
reasonably similar to a star's brightness curve, but he is unable to work
with anything simpler. Such as planetary orbits, for example. He throws up
a smokescreen of excuses for why Newton gets it wrong and GR gets it
right, and then moves on to a different subject that he can drag you down
into with his stupidity.
I don't expect much. :-) I've been surprised before, though. :-)
[.sigsnip]
--
#191,
It's still legal to go .sigless.
.
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